Uniparser

- parse_callback handle context arg
- add benchmark

- fix demo choices
- update UI
- fix curlparse issue; sync code as torequests
- add req as alias for context['request_args']
- remove parse_validator, using parse_callback
- support cache rule in web UI

- fix context logic
- allow import by default; renamed _FORBIDDEN_FUNCS
- support parse_validator for Uniparser
- support custom args for CrawlerRule in UI

- add alias name obj for python.template parser
- fix real request_args for context while crawling
- add HostRule.findall
- add base64 and re for UDF
- update some UDFParser._DANGEROUS_WORDS
- add int index for PythonParser
- refactor _DANGEROUS_WORDS_REGEX
- support non-http request ignore downloading

- fix compatible args
- add demos for parsers on web UI

support reset parser rule's order with web UI